Cycle chain adjuster



Aug. 22, 1950 F, W, GRAF-F 2,519,901

CYCLE CHAIN ADJUSTER Filed June 10, 1948 1N VEN TOR.

Patented Aug. r22, 1950 Frederick W. Gral, Sheboygan, Wis., assigner to-Garton ToylOompany, Sheboygan, Wis., a corporation of WisconsinApplication June 1o, 1948, serial No. 32,081

(iol. 'i4-242.14)

3 Claims.

This invention relates to improvements in cycle chain adjusters.

ln conventional cycle structures motive power is transmitted from thepedal-equipped crank to the rear axle by an endless chain trained voversprockets. The chain will require adjustments to maintain it in theproper degree of tautness, and heretofore this has been accomplished bymounting the rear axle of the cycle in slots or forks in the rear of theframe with cooperating adjusting bolts to shift the axle fore and aft tothereby tighten or loosen the chain. The conventional cycle chainadjusting structure mentioned is open to a number of objections anddisadvantages. In the rst place adjustment of the chain through movementof the rear axle required manipulation and equalization of two boltswhich were inconvenient to apply a tool to and which, if not adjustedprecisely equally would result in non-alinement of the rear wheel orwheels of the cycle. Also a complicated rear fork construction wasrequired because of the slots.

With the above in mind it is a primary object of the present inventionto overcome the objections and disadvantages inherent to conventionalstructures of the character described by providing a chain adjuster forcycles which displaces the usual pedal crank hub and substitutes amounting for the intermediate portion of a pedal crank which can beeasily adjusted fore and aft f,

to shift with it the forward chain sprocket to thus adjust the chain,the rear wheel axle and wheel remaining unaffected whereby mis-alinementof the rear wheel or wheels is not a problem.

A further object of the invention is to provide a cycle chain adjusterwhich employs but a single, very accessible adjusting bolt, and chainadjustments may be accomplished by a novice without throwing any partsof the assemblage out of alinement.

A further object of the invention is to provide a cycle chain adjusterin which the pedal crank is shiftable in a rectilineal path.

A further object of the invention is to provide a cycle chain adjusterwhich may be readily incorporated in a two or three wheeledpedaloperated cycle in a manner so that the cycle struc- In theaccompanying drawing in which the same reference characters indicate thesame parts in all of the views:

Fig. l is a fragmentary side view of a pedal operated cycle equippedwith the improved chain adjuster, parts being broken away and insection;

Fig. 2 is an enlarged, fragmentary view of the intermediate frameportion of a cycle equipped with the improved chain adjuster whichcarries the pedal crank, portions being shown in section and taken online 2-2 of Fig. 3;

Fig. 3 is a sectional view taken on line 3-3 of Fig. 2; and

Fig. 4 is a sectional View taken on line 4-4 of Fig. 3.

Referring new more particularly to the drawing it will appear that acycle frame is indicated generally by the numeral IIJ. The improvedchain adjuster is applicable to any type of pedal-opwardly through slotsI6 therefor in the shell I3.

The improved chain adjuster includes a hollow drum-like casing Ilhaving, in its annular wall, openings I8 which are entered by' the endportions of frame bars I9, 2Q and 2 I, which end por-v tions of saidframe bars are welded or otherwise ture is extremely neat and simple,which is strong secured to the stock of the casing I'I surround- K andthe same houses ball bearings 23 which revolubly engage crank sleeves 24positioned axially of said crank hub and extending beyondv the oppositeends thereof. Having a .force t within the crank sleeves 24' is theintermediate portion of a pedal crank 25 projecting laterally of bothends of the hub and sleeves. Closing the opposite faces or ends of thecasing I'I are flanged cover plates 26, each having a centrally locatedelongated, ovate opening 21 through which the opposite ends of the crankhub adjustably project. Each cover plate 26 is also formed, above andbelow its opening 21, with an elongated connecting bolt slot 28. Aixedto the crank hub 22 intermediate its ends is the inner end of a hubadjusting bolt 29. The latter extends outwardly through an openingtherefor in the annular wall of the casing l1. On the outwardlyprojecting threaded shank portion of the bolt 29 are suitable washers 3land an adjusting nut 32.

The chain adjuster assemblage is completed by outer collar plates 33applied exteriorly of the plates 26 and having central flanged collarportions 34 which receive and eng-age the outer extremities of the crankhub 22. Holes 351m said plates 33 register with the slots 28 in theplates 26 and receive elongated connecting bolts 36 whereby the entirechain adjuster assemblage is detachably and adjustably maintainedinassembled condition. The outer threaded extremities of Said bolts 36carry nuts 31 which may be loosened when adjustments are to be made sothat the shank portions of thev bolts may shift inl the plate slots 28.

As will be noted from Fig. 1 an end of the i11- terrmediate portion ofthe pedal crank 25 carries fast thereon. a large. sprockety 38. Avforward portion of the endless chain I5 engages said sprocket 3B. Thepedal crank is turned by foot power ap plied. to the pedals 39 and thelarge sprocket is thereby turned with the driving power being transmitedto the rear axle ll andther wheels l2 by the chain I5. Itis theobjective'to the present invention to provide easily operated andreadily accessible means for tightening or loosen-V ing said chainwithout throwing the wheels or rear axle out of their proper alinement.The improved chain adjuster provides for this and functions throughmovement forwardly or rearwardly. in ai desirable rectilinear path.

Obviously, to accomplish an adjustment of the chain I5 the nut 32-on thehub adjusting boltr29 should be turned inwardly or outwardly bya4 toolapplied thereto, depending onwhetherthe chain is to be tightened orloosened. The. drum-- like casing H, being ailixed to the frameI l0,ire-- mains. stationaryv and the; connected assemblage` which includesthe cran-k hub` 22, the crank" sleeves'ZG, the pedal crank 25, the pairsof plates 26 and 33', and the elongated: connectingy bolts 36v isdrawnfore or aft the desired distance to ac'- compl-ish the properadjustment ot the chain. The plate slots 26 permitI this movement and:hence, before making' the adjustment, the nuts 31 on the connectingbolts; 36. shouldbe loosened slightly. Also during the adjustingmovement the ovate openings 21 in the casing coverY plates 2liaccommodate back, and forth movement of the crank hub 22 and parts4carried thereby.

From the foregoing descriptionit `will be evident that the improvedcycle chain adjuster isr readily applicable tovarious types of cycles,gresuits; infa simplified rear: frame `c onstructiorr,, is: easy tomanipulate, and is well' adapted for the purposes described.

What isclaimed as the invention is:

1. A cycle chain adjuster, comprising a cycle: frame-carried casing, ahub member, pin and'slot means operatively mounting' the hub: memberyin.

said casing for back and forth adjustments in a path transverse to theaxis of the hub member, said casing having an opening in its wall, abolt xed to said hub at right angles to the axis of said hub andprojecting slidably through said casing opening, a nut threaded onto theouter end portion of said bolt adjacent said casing wall, a crankrevolubly mounted through said hub member, a sprocket fast on saidcrank, and a motion transmitting chain engaging said sprocket.

2. A cycle chain adjuster, comprising a cycle frame-carried drum-likecasing, a hub member, means operatively mounting the hub member in said.casing for back and forth adjustments in a rectilinear path transverseto the axis of the hub member, manually operated means to effect backand forth adjustments of said hub member and tosecure-the sameV in aposition of adjustment, a pedal crank revolubly mounted through said hubmember and casing and projecting beyond both ends of the casing,anti-friction devices interposed between the pedal crank and-the hubmember, a sprocket fast on a portion of said crank exteriorly of saidcasing, and a` motion transmitting chain engaging said sprocket andadjustable through back and forth movements of the hub member.

3'. The combination with a cycle frame carrying a rear driven axle witha sprocket fast thereon anda motion transmitting endless chain-extendingforward-1yl from said sprocket, of a, device for' adjusting' the tensionof said chain, comprising a drum-like casing xedly carried by a lowerinter-A mediate portion of the cycle frame, a hubmember, the axis ofsaid hub member being parallel tosaid rear axle, pinsandslot meansoperatively mounting the hub member in said casing for back and forthadjustments in a path transverse to the axis of the hub member, saidcasing having an opening in its wall, abolt fixed to said hub at rightangles tothe axis of said hub andJ projecting slidably through saidcasi-ng opening, a nut threaded onto the outer end portion of said bolt'to impinge against the casing, a pedal crank revo'lubl-y mounted throughsaid hub member and casing', anti-friction devices interposed betweenthe pedal crank and the hubmember, andy a sprocket fast on a portion ofsaid peda-l crank exteriorly-ofvsaid casing and engaged by a forwardporti'onof said endless' chain, back and forth adjustments ofV said hubmember being eective to regulate the tension of said? cha-in.

FREDERICK W. GR'AFF.

REFERENCES CITED The following references arev of record in' the fileofthis patent:

UNITED STATES PATENTS- Number: N ame' Date 406,461 Overman July 9, 1889'459,003 Hanson Sept. 8,.1891 5863912V Osmond July' 20', 1897 666,445 Vonder Heyde Jan. 22311901

